[PATCH v2 8/9] trace2: add counter events to perf and event target formats
- From
- Jeff Hostetler via GitGitGadget <gitgitgadget@gmail.com>
- Date
- Dec 28, 2021, 19:36 UTC
- Message-ID
- <0ef23190759710451bf912a38fbc420d4452800b.1640720202.git.gitgitgadget@gmail.com>
- In-Reply-To
- <pull.1099.v2.git.1640720202.gitgitgadget@gmail.com>
From: Jeff Hostetler <jeffhost@microsoft.com>
Teach Trace2 "perf" and "event" formats to handle "counter" events for global counters. Update the API documentation accordingly.
In a future commit, global counters will be added to the Trace2 API and it will emit these "counter" events at program exit.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> --- Documentation/technical/api-trace2.txt | 19 +++++++++++++++++++ trace2/tr2_tgt.h | 14 ++++++++++++++ trace2/tr2_tgt_event.c | 23 +++++++++++++++++++++++ trace2/tr2_tgt_normal.c | 1 + trace2/tr2_tgt_perf.c | 18 ++++++++++++++++++ 5 files changed, 75 insertions(+)
diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt index 616001bcbb0..bdba0f92280 100644 --- a/Documentation/technical/api-trace2.txt +++ b/Documentation/technical/api-trace2.txt @@ -838,6 +838,25 @@ may exceed the "atexit" elapsed time of the program. Timer events may represent an individual thread or a summation across the entire program. Summation events will have a unique thread name. +`"counter"`:: + This event is generated at the end of the program and contains + the value of a global counter. ++ +------------ +{ + "event":"counter", + ... + "name":"test", # counter name + "value":42, # value of the counter +} +------------ ++ +A global counter can be incremented throughout the execution of the +program. It will be reported in a "counter" event just prior to exit. ++ +Counter events may represent an individual thread or a summation across +the entire program. Summation events will have a unique thread name. + == Example Trace2 API Usage Here is a hypothetical usage of the Trace2 API showing the intended diff --git a/trace2/tr2_tgt.h b/trace2/tr2_tgt.h index a41f91d09b5..66f34b9258f 100644 --- a/trace2/tr2_tgt.h +++ b/trace2/tr2_tgt.h @@ -120,6 +120,19 @@ typedef void(tr2_tgt_evt_timer_t)(uint64_t us_elapsed_absolute, uint64_t ns_min_time, uint64_t ns_max_time); +/* + * Item counter event. + * + * This also does not take a (file,line) pair. + * + * The thread name is optional. + */ +typedef void(tr2_tgt_evt_counter_t)(uint64_t us_elapsed_absolute, + const char *thread_name, + const char *category, + const char *counter_name, + uint64_t value); + /* * "vtable" for a TRACE2 target. Use NULL if a target does not want * to emit that message. @@ -157,6 +170,7 @@ struct tr2_tgt { tr2_tgt_evt_data_json_fl_t *pfn_data_json_fl; tr2_tgt_evt_printf_va_fl_t *pfn_printf_va_fl; tr2_tgt_evt_timer_t *pfn_timer; + tr2_tgt_evt_counter_t *pfn_counter; }; /* clang-format on */ diff --git a/trace2/tr2_tgt_event.c b/trace2/tr2_tgt_event.c index fe89e80bb1a..907bff80827 100644 --- a/trace2/tr2_tgt_event.c +++ b/trace2/tr2_tgt_event.c @@ -643,6 +643,28 @@ static void fn_timer(uint64_t us_elapsed_absolute, jw_release(&jw); } +static void fn_counter(uint64_t us_elapsed_absolute, + const char *thread_name, + const char *category, + const char *counter_name, + uint64_t value) +{ + const char *event_name = "counter"; + struct json_writer jw = JSON_WRITER_INIT; + double t_abs = (double)us_elapsed_absolute / 1000000.0; + + jw_object_begin(&jw, 0); + event_fmt_prepare(event_name, __FILE__, __LINE__, NULL, &jw, thread_name); + jw_object_double(&jw, "t_abs", 6, t_abs); + jw_object_string(&jw, "name", counter_name); + jw_object_intmax(&jw, "value", value); + + jw_end(&jw); + + tr2_dst_write_line(&tr2dst_event, &jw.json); + jw_release(&jw); +} + struct tr2_tgt tr2_tgt_event = { &tr2dst_event, @@ -675,4 +697,5 @@ struct tr2_tgt tr2_tgt_event = { fn_data_json_fl, NULL, /* printf */ fn_timer, + fn_counter, }; diff --git a/trace2/tr2_tgt_normal.c b/trace2/tr2_tgt_normal.c index 23a7e78dcaa..1778232f6e9 100644 --- a/trace2/tr2_tgt_normal.c +++ b/trace2/tr2_tgt_normal.c @@ -356,4 +356,5 @@ struct tr2_tgt tr2_tgt_normal = { NULL, /* data_json */ fn_printf_va_fl, NULL, /* timer */ + NULL, /* counter */ }; diff --git a/trace2/tr2_tgt_perf.c b/trace2/tr2_tgt_perf.c index c07ffad1a32..911cf6e6eab 100644 --- a/trace2/tr2_tgt_perf.c +++ b/trace2/tr2_tgt_perf.c @@ -581,6 +581,23 @@ static void fn_timer(uint64_t us_elapsed_absolute, strbuf_release(&buf_payload); } +static void fn_counter(uint64_t us_elapsed_absolute, + const char *thread_name, + const char *category, + const char *counter_name, + uint64_t value) +{ + const char *event_name = "counter"; + struct strbuf buf_payload = STRBUF_INIT; + + strbuf_addf(&buf_payload, "name:%s value:%"PRIu64, counter_name, value); + + perf_io_write_fl(__FILE__, __LINE__, event_name, NULL, + &us_elapsed_absolute, NULL, + category, &buf_payload, thread_name); + strbuf_release(&buf_payload); +} + struct tr2_tgt tr2_tgt_perf = { &tr2dst_perf, @@ -613,4 +630,5 @@ struct tr2_tgt tr2_tgt_perf = { fn_data_json_fl, fn_printf_va_fl, fn_timer, + fn_counter, };
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